1. Field of the Invention
The present invention discloses an improvement in an eye fundus camera and more particularly an improved illumination optical system for aligning the pupil of the eye with the eye fundus camera.
2. Description of the Prior Art
Eye fundus cameras are known in the ophthalogical field for permitting diagnosis of the condition of a patient. A recurrent problem in the use of these instruments comprises the alignment of the center line of the patient's pupil with a photographic optical axis prior to any photography. Generally, this alignment procedure is accomplished by a naked eye monitoring of the front of the eye from a position outside of the photographic optical path.
When working with a non-mydriasis eye fundus camera, no visible light is employed during the prephotographing procedures, and accordingly, alignment cannot be made, simply by the use of the naked eye. It has been suggested in a non-mydriasis fundus camera to use an infrared fundus monitoring system for focus setting. Problems, however, still exist with respect to a precise alignment of a pupil on a photographic axis in a relatively simple procedure.
The following U.S. patents are cited of general interest to disclose various eye fundus cameras that have sought to provide alignment of the pupil with the photographic optical axis, U.S. Pat. No. 4,068,932, U.S. Pat. No. 3,936,844 and U.S. Pat. No. 3,925,793.
The prior art is still seeking a relatively uncomplicated and positive method of aligning the pupil of the eye in an eye fundus camera.